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Analog Temperature Sensor – LM335

Rev 1.1

28/04/20

COORDINATES (µm)

PAD

FUNCTION

X

Y

1

V+

134

848

2

V-

1281

103

3

ADJ

1268

848

CONNECT CHIP BACK TO V- OR FLOAT

Pad Layout and Functions

Simplified Schematic

1500µm (59.06 mils)

Calibration methodology and schematic

0,0

3

1

2

10mV/°K

The LM335 response is proportional to absolute temperature with the

extrapolated output of sensor going to 0V at 0°K (-273.15°C). Errors in output

voltage versus temperature are only slope. Thus a calibration of the slope at

one temperature corrects errors at all temperatures. The circuit output

(calibrated or not) is given by the equation:

Where:



T is the unknown temperature



Nominally, the output is calibrated at 10mV/°K.

T

Application Note:

Self-heating can decrease accuracy; LM335 should be operated at low current but sufficient enough to drive the

sensor and calibration circuit to the maximum operating temperature. If used in surroundings where the thermal

resistance is constant, the errors due to self-heating can be externally calibrated. This is possible if the circuit is biased

with a temperature stable current. Heating will then be proportional to Zener voltage and therefore temperature. In this

way, the error due to self-heating is proportional to the absolute temperature as scale factor errors.

10mV/°K

10kΩ*

* Calibrated for

2.982V at 25°C